Please enter values for heart rate or RR interval and QT interval.
QTc values are rounded to milliseconds.
Transgression of QTc limits is indicated by colors yellow and red, according to the ESC guidelines of 2015 – see below.
For formulae, see below.
Unfortunately, the limits for Long and Short QT Syndrome are disputed. According to one of the most recent publications (ESC Guidelines, 2015):
QT interval (Wikipedia)
Long QT Syndrome (Wikipedia)
Short QT Syndrome (Wikipedia)
The following representation is based on a study by Funada et al., 2008, with 10,984 Japanese subjects (50 % males):
In males, QTcBzt was 404 ± 25msec (gray).
In females, QTcBzt was 412 ± 24 msec (gray).
At a measured QT of 360 ms, QTc is the following depending on heart rate:
There is a version of this QTc calculator for iPhone and iPad: four correction formulas, graphical representation of results and a small knowledge base. more
correction formula: QTcBzt = QT / √RR
published in 1920; 39 subjects
original publication: https://onlinelibrary.wiley.com/resolve/doi?DOI=10.1111/j.1542-474X.1997.tb00325.x
Sometimes spelled “Fredericia”.
correction formula: QTcFri = QT / ∛RR
published in 1920; 50 subjects
original publication: https://onlinelibrary.wiley.com/doi/abs/10.1111/j.0954-6820.1920.tb18266.x
correction formula (for msec): QTlc = 1000 (QT + 0.154 (1 – RR))
published in 1992; 5,018 subjects, more information about the Framingham Heart Study (Wikipedia)
original publication: https://www.ajconline.org/article/0002-9149(92)90562-D/pdf
published in 1983, 607 subjects
original publication (page 694): http://www.onlinejacc.org/content/1/2_Part_2/577
RR = 60 / HR
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